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Table 3 Genotype-phenotype correlation in index cases homozygous for SMN1 deletion

From: Spinal muscular atrophy in Venezuela: quantitative analysis of SMN1 and SMN2 genes

FamilyCaseSexClinical featuresSMN2 copiesOnset ageSMA type
1IFWithout cephalic support, severe hypotonia, developed respiratory distress and pneumonia at 5 months of age. Died from respiratory complications at 9 months of age1< 6 monthsI
2IFWithout cephalic support, severe hypotonia, progressive respiratory distress. Died from respiratory complications at 16 months of age2
3IFGeneralized hypotonia at 6 months of age. Can stand and walk with support at 3 years old. Bilateral Babinski sign. Abolished osteotendinous reflexes, joint laxity. Decreased weight and height (P7)2> 6 monthsII
4IFHypotonia, progressive delay in motor development. Can stand up and walk with difficulty2
5IFLower limbs weakness at 8 months of age. Hypotonia, hyperlordosis, kyphosis, abolished osteotendinous reflexes, joint laxity. Decreased weight and height (P7). Can stand up with support but cannot walk at 5 years old.4
6IFMotor regression from 8 months of age. Lower limbs hypotonia, cannot crawl, sit, or walk at 2 years old. Abolished osteotendinous reflexes.4
7I (III-7)aMSevere hypotonia, inability to get up or walk without support, fine tremor of tongue, hands, and feet.1
7II (III-8)aMHypotonia, affectation, and gradual weakness in proximal and distal muscles, EMG and muscle biopsy compatible with SMA2
7III (III-3)aMHypotonia, affectation, and gradual weakness in proximal and distal muscles, EMG and muscle biopsy compatible with SMA3
8IFGeneralized hypotonia, muscle hypotrophy. At 3 months, she had head support, currently she cannot sit or stand without support.2
9IMGeneralized hypotonia. Unable to stand or walk without support. No cephalic support. EMG compatible with SMA.2
10IFHypotonia. Cephalic support. Decreased muscle strength. Muscle atrophy in lower limbs. EMG compatible with SMA.4
10II (A.F.)--3
11IFUnable to stand or walk without support. She had cephalic support. Generalized muscular spasticity, muscle weakness, tongue fasciculations. EMG compatible with AME3-
  1. (A.F) amniotic fluid sample
  2. aIndividuals’ identification in Fig. 1